Rheostat arm



May 18 1926.

M. A. SZUKALSKI ET AL RHEOS TAT ARM Filed March 26, 1925 MVJ PatentedMay 18, 1926.

UNITED STATES MARIAN A. SZUKALSKI AND MARIAN F. SZUKALSKI, J 3., OFMILWAUKEE, WISCONSIN.

1,585,214 PATENT OFFICE.

RHEOS'IAT ARM.

Application filed March 26, 1925. Serial No. 18,417.

This invention relates to rheostats, and is particularly directed to arheostat arm..

In rheostats in which a traveling arm passes over a resistance,diiliculty has been experienced in maintaining a positive electricalcontact between the arm and the resistance, and further due toirregularity in the manufacture of resistance such as the coil wireemployed in rheostats in radio apparatus, a scraping or rough, unevenaction results.

This invention is designed to overcome the above noted defects, andobjects of the invention are to provide a rheostat in which a positiveelectrical contact is insured at all positions of adjustment between thearm and the resistance, and in which a free and easy travel of the armis insured irrespective of variations in the surface of the resistancedue to errors in manufacture.

This invention, although applicable to rheostats in general, isparticularly applicable to rheostats employed with radio apparatus in.which the scraping and uneven action is highly detrimental, and suchinvention, therefore, provides a rheostat which may be successfully usedwith radio apparatus to secure the exact adjustment desired without thepresence of an irregular or jerky action. 7

An embodiment of the invention is shown in the accompanying drawings, inwhich Figure 1 is a bottom plan View of one form of rheostat showing thearm in posi- .tion.

Figure 2 is a transverse sectional view 3 throu h the rheostat.

sleeve 4 and is in intimate contact with the.

sleeve throughout its extent.

It is to be noted that the rear end of the adjusting spindle 6 passesthrough the hub 7 of the arm 8, such hub being provided with a set screw9 to lock it to the spindle.

Further, it will be noted that the spindleet is electrically connectedto the strap 10 which is secured to one of the outlet or terminal endsor connectors of the rheostat, the

other terminal of the rheostat being connected to the other end of theresistance 3 in the usual manner.

A convenient way of making the arm 8 is to give it a 'platelikeformation and to rigidly secure it to the hub 7 in any suitable manner.This arm is provided with upstanding bearings 11, 12 and 13 whichreceive a small shaft 14, such shaft extending axially of the arm. It istobe noted that the arm 8 is cut away adjacent its forward end, asindicated at 15 and that a contact roller 16 is rigidly secured to ,theshaft 14 and operates through the cut out 15, such roller contactingwith the resistance 3. It is to be noted, of course, that the arm 8 isspringy and is given a slight tension towards the resistance 3 to pressthe roller against the resistance element.

In order to insure a permanent electrical connection between the roller16 and the shaft 14, an elongated helical spring 17 has its outer endrigidly secured to the shaft and its inner end rigidly secured, asindicated at 18, to the arm 8.

In using the apparatus, the roller travels over the resistance elementand in one direction of rotationwinds the spring 17 slightly. Thisspring, however, is of sufficient length to permit this winding withoutundue stresses. Obviously, when the arm is rocked in thereverse-direction, the spring is unwound to its original state. However,at all times, the roller is permanently electrically connected to thearm 8, irrespective of its rotary motion.

If desired, this inventive idea may be carried out further by providinga similar spring or connecting member 19 permanently connecting the hub7 with the stationary arm 10.

It will be seen, therefore, that a rheostat arm construction has beenprovided in which a roller is employed to freely pass over theirregularities in the resistance element, and in which the roller ispermanently electrically connected with the arm irrespective of itsposition of adjustment.

Although the invention has been described in considerable detail, it isto be understood that the invention may be variously embodied and is,therefore, to be limited only as claimed.

We claim:

1. A rheostat arm comprising an elongated member adapted to be connectedto a roller rigidly mounted upon said shaft ad jacent its outer end, ahelical spring loosely surrounding said shaftand having one end rigidlysecured thereto and its other end rigidly secured to said arm:

2. A rheostat comprising a body portion, an elongated resistance elementcarried thereby, a movable rocking arm pivotally carried by said bodyportion, a shaft carried by said arm, a roller rigidly secured to saidshaft adjacent the outer end. of said arm and contacting with saidresistance, a flexible electrical conductor rigidly secured at one 'endto said shaft, and at its other end 'to said arm, and a second flexibleelectric conductor having one end rigidly connected to the inner portionof said arm, a

terminal member rigidly connected to the other end of said secondflexible conductor,

and a second terminal member connected to one end of said resistance.

3. A rheostat comprising a body portion, a--resistance element carriedby said body portion, an arm movably supported by said body portion, ashaft'revolubly carried by said arm, a roller contacting with andadapted to travel over said resistance element, said roller beingrigidly secured to said shaft, and a flexible electrical conductorhaving one end rigidly connected to said shaft and adapted to be rotatedtherewith and having its other end rigidly fastened to said arm.

In testimony that We claim the foregoing We have hereunto set our handsat Milwaukee, in the county of Milwaukee and State of lVisconsin. I

MARIAN A. SZUKALSKI. MARIAN F. SZUKALSKI, J n.

